Title

Author

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Dr. Raouf E Baddour

Abstract

The main objective of this thesis is to study the hydraulic behaviour of a surface heated discharge in a shallow channel, which is wider than the discharge of thermal waste, and connected to a colder water body. An internal hydraulic jump characterized by mixing (dilution) of hot and cold water was observed in the channel. Similar to the single-layer hydraulic jump, the internal hydraulic jump in a two-layer system is a rapid transition from supercritical to subcritical flow.

The study involved analytical and experimental analyses of the flow in the channel. The analytical analysis showed that the critical dilution initially increased with the Initial Froude Number (Fr0) up to a specific value of Fr0. This specific condition defined the maximum critical dilution point for a particular shallow channel. Beyond this maximum critical point, dilution decreased with the increase in the Fr0 . In comparison, there is no maximum critical dilution point in a deep channel and the critical dilution always increases with the increase of the Fr0 .

Experiments were performed in a laboratory apparatus. The cooling channel compartment of the apparatus was the most essential part of this study. Mixing, back flow, internal hydraulic jump, and ambient water entrainment took place inside this cooling channel. Two side weirs were also provided to control the depth of the water inside the channel. The temperature was measured with an array of thermocouples connected to a computer data acquisition system. The width of the channel was fixed but the depth was changed from experiment to experiment.

The experimental results confirmed that the critical dilution in the channel had a maximum value. At high Froude numbers the depth of the jump reached the bottom of the channel. The hot water discharge did not mix with ambient water when the jump reached the bottom of the channel.

Analytical and experimental results were directly compared by plotting the maximum dilution µmax vs. Fr0 . The experiments confirmed the analytical predictions of dilution in a cooling channel of limited depth and finite width.